U.S. patent number 9,038,549 [Application Number 13/827,333] was granted by the patent office on 2015-05-26 for height adjustable table.
This patent grant is currently assigned to Humanscale Corporation. The grantee listed for this patent is Humanscale Corporation. Invention is credited to Hamid Zebarjad.
United States Patent |
9,038,549 |
Zebarjad |
May 26, 2015 |
Height adjustable table
Abstract
A height adjustable table, which has a constant-force
counterbalance mechanism integrated into a top assembly of the
table is disclosed. The height adjustable table can include a top
assembly supported by a base assembly, which can include right and
left telescoping leg assemblies. The top assembly can include a
work surface supported by a housing. A counterbalance mechanism,
which can include a spring coupled to a snail cam pulley, can be
mounted within the housing. A synchronized lift mechanism, which
can include at least two bands operatively engaged with a pulley
system disposed within the right and left telescoping leg
assemblies, can be operatively coupled to the snail cam pulley such
that the counterbalance force provided by the counterbalance
mechanism is transmitted to the synchronized lift mechanism.
Inventors: |
Zebarjad; Hamid (New York,
NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Humanscale Corporation |
New York |
NY |
US |
|
|
Assignee: |
Humanscale Corporation (New
York, NY)
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Family
ID: |
53176236 |
Appl.
No.: |
13/827,333 |
Filed: |
March 14, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61654609 |
Jun 1, 2012 |
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Current U.S.
Class: |
108/147;
108/33 |
Current CPC
Class: |
A47B
9/02 (20130101); A47B 9/20 (20130101); A47B
9/12 (20130101); A47B 2200/0052 (20130101) |
Current International
Class: |
A47B
9/20 (20060101) |
Field of
Search: |
;108/37,33,144.11,147,147.19,136
;248/188.2,161,404,157,162.1,123.11,122.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2009218798 |
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Sep 2009 |
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AU |
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101965140 |
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Feb 2011 |
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CN |
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102008010768 |
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Aug 2009 |
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DE |
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1987734 |
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Dec 2010 |
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EP |
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2254440 |
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Dec 2010 |
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EP |
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0174197 |
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Oct 2001 |
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WO |
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2009106292 |
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Sep 2009 |
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WO |
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2011025561 |
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Mar 2011 |
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WO |
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Other References
Teknion Corporation, Teknion Tables, Quick Shift online brochure,
May 3, 2007, 8 pages. cited by applicant .
Steelcase, Inc., Airtouch online brochure, Feb. 2, 2011, 5 pages.
cited by applicant .
Ki, WorkUp Adjustable Table online brochure, Mar. 19, 2012, 4
pages. cited by applicant .
Global Upholstery Co., Inc., Height Adjustable Tables online
brochure, Jan. 26, 2001, 2 pages. cited by applicant.
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Primary Examiner: Rohrhoff; Daniel
Attorney, Agent or Firm: Jones Walker LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application
No. 61/654,609, filed Jun. 1, 2012, which is hereby incorporated by
reference.
Claims
What is claimed is:
1. A height adjustable table comprising: a top assembly comprising
a housing and a work surface supported on the housing; a
constant-force counterbalance mechanism disposed within the
housing; a base assembly, which supports the top assembly, the base
assembly comprising a first telescoping leg assembly and a second
telescoping leg assembly, the first telescoping leg assembly and
the second telescoping leg assembly each comprising an outside leg
and an inside leg having a variable overlap to accommodate height
adjustment of the top assembly; and a preload mechanism positioned
within the housing and operatively coupled to the constant-force
counterbalance mechanism, the preload mechanism comprising: a
gearbox having a worm wheel; a worm meshed with the worm wheel to
form a worm drive; a hub coupled to the worm wheel; a preload cable
having a first end attached to the hub and a second end attached to
the constant-force counterbalance mechanism; and a handle coupled
to the worm drive.
2. The height adjustable table of claim 1, wherein the
constant-force counterbalance mechanism comprises: a tension spring
for providing a counter-weight force, the tension spring having a
first end and a second end; a snail cam pulley comprising a snail
cam wheel secured to a mount by an axle, the snail cam wheel having
a cam track and a lift track; and a snail cable coupling the second
end of the tension spring to the cam track of the snail cam
wheel.
3. The height adjustable table of claim 2, further comprising a
synchronized lift mechanism operatively coupled to the
constant-force counterbalance mechanism to provide synchronized
lifting or lowering of the top assembly, the synchronized lift
mechanism comprising: a first pulley assembly and a second pulley
assembly, the first pulley assembly associated with the first
telescoping leg assembly and the second pulley assembly associated
with the second telescoping leg assembly; a first band and a second
band each operatively coupled to the first and second pulley
assemblies; and a lift cable having a first end attached to the
lift track of the snail cam wheel and a second end attached to the
inside leg of one of the first and second telescoping leg
assemblies.
4. The height adjustable table of claim 2, further comprising a
load indicator coupled to the first end of the tension spring.
5. The height adjustable table of claim 3, wherein each of the
first and second pulley assemblies comprises: at least one upper
pulley; at least one lower pulley; and a shaft coupling the at
least one lower pulley to the at least one upper pulley, wherein
the shaft is suspended within an internal cavity of the respective
telescoping leg assembly.
6. The height adjustable table of claim 5, wherein a first end of
the second band is connected to the inside leg of the first
telescoping leg assembly and extends around the at least one upper
pulley of the first pulley assembly, across the housing, around the
at least one upper pulley of the second pulley assembly, around the
at least one lower pulley of the second pulley assembly, and
connects at a second end to the inside leg of the second
telescoping leg assembly.
7. The height adjustable table of claim 3, further comprising a
lock mechanism positioned within the housing for fixing the top
assembly at a desired height, the lock mechanism comprising: a lock
assembly having a release position and a lock position, the lock
assembly having upper and lower lock members positioned on opposing
sides of at least one of the first and second bands and configured
to prevent height adjustment of the top assembly when the lock
assembly is positioned in the lock position; and a release assembly
having an actuation member, a safety spring, a first cable
connecting the actuation member to the safety spring, and a second
cable connecting the safety spring to the lock assembly.
8. The height adjustable table of claim 5, wherein the lift cable
extends from the lift track around the at least one upper pulley of
the first pulley assembly and around the at least one lower pulley
of the first pulley assembly, and attaches to the inside leg of the
first telescoping assembly.
9. The height adjustable table of claim 5, wherein the lift cable
extends from the lift track around the at least one upper pulley of
the second pulley assembly, around the at least one lower pulley of
the second pulley assembly, and attaches to the inside leg of the
second telescoping assembly.
10. The height adjustable table of claim 6, wherein a first end of
the first band is connected to the inside leg of the second
telescoping leg assembly and extends around the at least one upper
pulley of the second pulley assembly, across the housing, around
the at least one upper pulley of the first pulley assembly, around
the at least one lower pulley of the first pulley assembly, and
connects at a second end to the inside leg of the first telescoping
leg assembly.
11. The height adjustable table of claim 1, wherein the preload
mechanism further comprises a torque limiter positioned between the
handle and the worm to decouple the handle from the worm drive when
a torque exerted by the handle on the worm drive exceeds a
predetermined amount.
12. A height adjustable table comprising: a base assembly
comprising a first telescoping leg assembly and a second
telescoping leg assembly, each of the first telescoping leg
assembly and the second telescoping leg assembly comprising: an
outside leg; and an inside leg, one of the outside and inside legs
being fixedly coupled to a stationary foot, the outside and inside
legs having a variable overlap; a top assembly supported by the
base assembly, the top assembly comprising a work surface mounted
to a housing; a constant-force counterbalance mechanism positioned
within the housing; and a synchronized lift mechanism operatively
coupled to the constant-force counterbalance mechanism to provide
synchronized lifting and lowering of the top assembly relative to
the stationary feet of the base assembly, the synchronized lift
mechanism comprising: a first pulley assembly positioned within the
first telescoping leg assembly; a second pulley assembly positioned
within the second telescoping leg assembly; a first band
operatively coupled to the first and second pulley assemblies; a
second band operatively coupled to the first and second pulley
assemblies; and a lift cable having a first end attached to the
constant-force counterbalance mechanism and a second end attached
to the inside leg of one of the first and second telescoping leg
assemblies.
13. The height adjustable table of claim 12, wherein the
constant-force counterbalance mechanism comprises: a snail cam
pulley including a snail cam wheel secured to a mount by an axle,
the snail cam wheel having a cam track and a lift track; a tension
spring having a first end and a second end; and a snail cable
coupling the second end of the tension spring to the cam track of
the snail cam wheel.
14. The height adjustable table of claim 12, further comprising: a
preload mechanism positioned within the housing and operatively
coupled to the constant-force counterbalance mechanism for
modulating a counter-weight force provided by the constant-force
counterbalance mechanism.
15. The height adjustable table of claim 14, further comprising a
lock mechanism positioned within the housing for fixing the top
assembly at a desired height, the lock mechanism comprising a lock
assembly having a release member and upper and lower lock members
positioned on opposing sides of at least one of the first and
second bands to prevent height adjustment of the top assembly.
16. The height adjustable table of claim 14, wherein the preload
mechanism comprises: a gearbox having a worm wheel; a worm meshed
with the worm wheel to form a worm drive; a hub coupled to the worm
wheel; a preload cable having a first end attached to the hub and a
second end attached to the first end of the tension spring; and a
handle coupled to the worm drive.
Description
BACKGROUND OF THE INVENTION
Recent research shows sedentary work increases the risk of cancer
and heart disease regardless of other health indicators such as
exercise and nutrition. However, standing all day in a static
position can also cause health problems, including a significant
increase in the risk of carotid atherosclerosis. The healthiest
workplace solution allows users to alternate between sitting and
standing positions throughout the day.
Height adjustable tables have been developed to allow a user to
change posture from a seated to a standing position throughout the
day. Height adjustable tables are ideally construed to have task
specific heights that are ergonomically correct. An ergonomically
correct position is one where the height of the work surface of a
table is at the user's elbows and where the height of the work
surface provides adequate leg room and knee space allowing a user
to feel uncrowded and to allow for some changes of position.
Existing height adjustable tables typically utilize either a hand
crank, an electric motor, or a counterbalance mechanism to adjust
the height of the work surface.
Counterbalance adjustable tables, which utilize either a
counterweight or a spring to offset the load on the work surface,
are advantageous over hand crank tables and electric tables since
the height of the work surface can be effortlessly adjusted without
consuming electricity. However, the counterbalance assemblies are
typically disposed either within the table's leg(s) or within a
cross-member beam extending between table's legs. For instance,
U.S. Pat. No. 7,658,359 discloses a single leg counterbalance table
having a compression spring disposed within a pedestal-type support
leg extending below the work surface. Meanwhile, U.S. Pat. No.
5,706,739 discloses a multi-leg counterbalance table having a
torsion spring disposed within a cross-member beam extending
between the table's legs. Disadvantageously, both arrangements
cause the table's support structure to be bulky, thereby reducing
leg room below the work surface.
Previous attempts have been made to develop a height adjustable
table, having a less bulky counterbalance mechanism, which does not
restrict leg room below the work surface. For instance, another
known height adjustable table features a counterbalance mechanism
comprising gas springs disposed within opposing table legs, with
each gas spring designed to provide a preset counterbalance force.
While such a table provides for more leg room by eliminating the
bulky cross-member beam, the counterbalance mechanism does not
accommodate for varying loads. If the load on the work surface
exceeds the counterbalance force, adjustment of the table's work
surface may require the user to exert an excessive amount of force.
Conversely, if the counterbalance force exceeds the applied load,
the work surface may surprisingly move rapidly and thus present a
safety hazard.
SUMMARY OF THE INVENTION
The invention disclosed herein is directed to a height adjustable
table having a constant-force counterbalance mechanism integrated
into the top assembly of the table. In a particular embodiment
exemplifying the principles of the invention, the height adjustable
table can comprise a top assembly supported by a base assembly. The
base assembly can comprise first and second telescoping leg
assemblies, with each leg assembly having outside and inside legs
featuring a variable overlap to accommodate height adjustment of
the top assembly. The top assembly can comprise a work surface
supported by a housing. The counterbalance mechanism, which can
comprise a tension spring coupled to a snail cam pulley by a snail
cable, can be mounted within the housing.
The height adjustable table of the present invention can also
feature a synchronized lift mechanism. The synchronized lift
mechanism can comprise at least two bands operatively engaged with
a pulley system disposed within the right and left telescoping leg
assemblies. The pulley system can comprise first and second pulley
assemblies each having an upper pulley and a lower pulley, with the
upper pulley being mounted to the top of the respective telescoping
leg assembly and the lower pulley being mounted to the end of a
shaft suspended within the internal cavity of the respective
telescoping leg assembly. The first end of the first band is
connected to the inside leg of the second telescoping leg assembly
and extends around the upper pulley of the second pulley assembly,
across the housing, around the upper pulley of the first pulley
assembly, around the lower pulley of the first pulley assembly, and
connects at a second end to the inside leg of the first telescoping
leg assembly. The first end of the second band is connected to the
inside leg of the first telescoping leg assembly and extends around
the at least one upper pulley of the first pulley assembly, across
the housing, around the at least one upper pulley of the second
pulley assembly, around the at least one lower pulley of the second
pulley assembly, and connects at a second end to the inside leg of
the second telescoping leg assembly.
The synchronized lift mechanism be operatively coupled to the
counterbalance mechanism by a lift cable. The lift cable snail cam
pulley by a lift cable. The lift cable can be attached to the lift
track of the snail cam wheel on one end and attached to the inside
leg of at least one of the first and second telescoping leg
assemblies at the other end. In this arrangement, the
counterbalance force provided by the counterbalance mechanism will
be transmitted to the synchronized lift mechanism.
In certain embodiments, a preload mechanism can be coupled to the
counterbalance mechanism to provide a means for preloading the
tension spring. The preload mechanism of the present invention
allows the counter-weighting force to be easily adjusted by users
to match the load (i.e., it is load-variable), thereby eliminating
the safety risk associated with non-load variable counterbalance
tables while also providing a work surface that can be moved up and
down with minimal effort. The height adjustable table may also
optionally include a lock mechanism for selectively preventing
height adjustment of the table.
The above summary is not intended to describe each illustrated
embodiment or every possible implementation. These and other
features, aspects, and advantages of the present invention will
become better understood with regard to the following description,
appended claims, and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying figures, where like reference numerals refer to
identical or functionally similar elements throughout the separate
views, which are not true to scale, and which, together with the
detailed description below, are incorporated in and form part of
the specification, serve to illustrate further various embodiments
and to explain various principles and advantages in accordance with
the present invention:
FIG. 1 is a front perspective view of an embodiment of a height
adjustable table exemplifying the principles of the present
invention wherein the table is in the lowered position;
FIG. 2 is a front perspective view of the embodiment of the height
adjustable table shown in FIG. 1 wherein the table is in the raised
position;
FIG. 3 is a bottom perspective view of the embodiment of the height
adjustable table shown in FIG. 1 wherein the table is in the
lowered position;
FIG. 4 is a top perspective view of the embodiment of the height
adjustable table shown in FIG. 1 wherein the work surface is
removed;
FIG. 5 is a top view of the embodiment of the height adjustable
table shown in FIG. 1 wherein the top of the housing is removed to
reveal embodiments of the constant-force counterbalance mechanism,
synchronized lift mechanism, preload mechanism, and lock mechanism
of the present invention;
FIG. 6 is a top view of the embodiment of the height adjustable
table shown in FIG. 1 wherein the work surface and the top of the
housing are removed to reveal the constant-force counterbalance
mechanism of the present invention;
FIG. 7 is a partial rear perspective view of the embodiment of the
height adjustable table shown in FIG. 1 showing the
interconnectivity of the constant-force counterbalance mechanism,
the synchronized lift mechanism, and the lock mechanism;
FIG. 8A is a perspective view of an embodiment of the snail cam
pulley of the present invention;
FIG. 8B is a top view of an embodiment of the snail cam wheel of
the present invention;
FIG. 9 is a view similar to the view of FIG. 5, except reference
numerals related to an embodiment of the synchronized lift
mechanism are shown;
FIG. 10 is a right-side perspective view of the embodiment of the
height adjustable table shown in FIG. 1;
FIG. 11 is a partial perspective view of an embodiment of the
height adjustable table's right leg assembly;
FIG. 12 is a partial perspective view of an embodiment of the
height adjustable table's left leg assembly;
FIG. 13 is a schematic illustration showing the interconnectivity
of the synchronized lift mechanism's first band to the right and
left leg assemblies of the height adjustable table of the present
invention;
FIG. 14 is a schematic illustration showing the interconnectivity
of the synchronized lift mechanism's second band to the right and
left leg assemblies of the height adjustable table of the present
invention;
FIG. 15 is a view similar to the view of FIG. 5, except reference
numerals related to an embodiment of the preload mechanism are
shown;
FIG. 16 is a top view of the embodiment of the preload mechanism
depicted in FIG. 15;
FIG. 17 is a perspective view of an embodiment of the preload
mechanism's gearbox;
FIGS. 18a, 18b, and 18c are perspective views of an embodiment of
the preload mechanism's torque limiter;
FIG. 19 is a perspective view of the embodiment of the preload
mechanism depicted in FIG. 15;
FIG. 20 is a top view of the embodiment of the preload mechanism
depicted in FIG. 15;
FIG. 21 is a view similar to the view of FIG. 5, except reference
numerals related to an embodiment of the lock mechanism are
shown;
FIG. 22 is a perspective view of an embodiment of the lock
mechanism's lock assembly;
FIG. 23 is a perspective view of another embodiment of the lock
mechanism's lock assembly; and
FIG. 24 is a perspective view of an embodiment of the lock
mechanism's release assembly.
DETAILED DESCRIPTION OF THE INVENTION
Detailed embodiments of the present invention are disclosed herein;
however, it is to be understood that the disclosed embodiments are
merely exemplary of the invention, which can be embodied in various
forms. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely
as a basis for the claims and as a representative basis for
teaching one skilled in the art to variously employ the present
invention in virtually any appropriately detailed structure.
Alternate embodiments may be devised without departing from the
spirit or the scope of the invention. Further, the terms and
phrases used herein are not intended to be limiting; but rather, to
provide an understandable description of the invention. While the
specification concludes with claims defining the features of the
invention that are regarded as novel, it is believed that the
invention will be better understood from a consideration of the
following description in conjunction with the drawing figures, in
which like reference numerals are carried forward.
As used herein, the terms "a" or "an" are defined as one or more
than one. The term "plurality," as used herein, is defined as two
or more than two. The term "another," as used herein, is defined as
at least a second or more. The terms "comprises," "comprising," or
any other variation thereof are intended to cover a non-exclusive
inclusion, such that a process, method, article, or apparatus that
comprises a list of elements does not include only those elements,
but may include other elements not expressly listed or inherent to
such process, method, article, or apparatus. An element proceeded
by "comprises . . . a" does not, without more constraints, preclude
the existence of additional identical elements in the process,
method, article, or apparatus that comprises the element. The terms
"including," "having," or "featuring," as used herein, are defined
as comprising (i.e., open language). The term "coupled," as used
herein, is defined as connected, although not necessarily directly,
and not necessarily mechanically. As used herein, the term "about"
or "approximately" applies to all numeric values, whether or not
explicitly indicated. These terms generally refer to a range of
numbers that one of skill in the art would consider equivalent to
the recited values (i.e., having the same function or result). In
many instances these terms may include numbers that are rounded to
the nearest significant figure. Relational terms such as first and
second, top and bottom, right and left, and the like may be used
solely to distinguish one entity or action from another entity or
action without necessarily requiring or implying any actual such
relationship or order between such entities or actions.
Herein various embodiments of the present invention are described.
To avoid redundancy, repetitive description of similar features may
not be made in some circumstances. Furthermore, certain views of
the embodiments of the present invention are duplicated (e.g.,
FIGS. 5, 9, 15, and 21) for ease of understanding the various
mechanisms employed by the present invention.
Prior art counterbalance tables typically have their counterbalance
mechanism disposed either within the table's leg(s) or within a
cross-member beam extending between table's legs.
Disadvantageously, such arrangements either cause the table's base
to be bulky and thus reduces leg room below the work surface, or
result in a table which is not capable of accommodating varying
loads. The present invention addresses these problems by
integrating a load-variable counterbalance mechanism into the top
assembly.
A height adjustable table embodying the principles of the present
invention is depicted in FIGS. 1-24. Referring to FIGS. 1-4, the
height adjustable table 1 can comprise a top assembly 100 supported
by a base assembly 200. The top assembly 100 includes a planar work
surface 101 mounted to a housing 102. The housing 102 can feature
plates 103, 104, 105 for stabilizing the work surface 101 on the
housing 102.
The base assembly 200 can comprise right and left telescoping leg
assemblies, with each leg assembly having an outside leg 202, a
middle leg 203, an inside leg 204, and a foot 210. The legs 202,
203, 204 have a variable overlap to accommodate height adjustment
of the work surface 101. The outside leg 202 is attached to the top
assembly 100 and thereby moves with the work surface 101 as it is
raised and lowered. The inside leg 204 is attached to the foot 210
and remains stationary as the work surface 101 is raised and
lowered. The right and left leg assemblies optionally can comprise
a roller cage 540 (See FIG. 10) containing a plurality of rollers
for facilitating frictionless sliding of the legs 202, 203, 204 as
the work surface 101 is raised and lowered. In alternative
embodiments, the inside leg 204 can be attached to the top assembly
100 and the outside leg 202 can be attached to the foot 210. In
such alternative embodiments, the inside leg 204 will move with the
work surface 101 as it is raised and lowered, while the outside leg
202 will remain stationary. In other alternative embodiments, the
right and left leg assemblies can comprise only an outside leg 202
and an inside leg 204, thus disposing of the middle leg 203; or
more than one middle leg 203 may be disposed between the outside
leg 202 and the inside leg 204.
Referring to FIGS. 5-8B, the height adjustable table 1 of the
present invention features a constant-force counterbalance
mechanism disposed within the housing 102. In most applications, it
is desirous for a height adjustable table's counterbalance
mechanism to provide a constant counter-weighting force to offset
the constant load on the work surface 101. The counterbalance
mechanism of the present invention utilizes a tension spring 310 to
provide the counter-weighting force. However, it is well known that
the force exerted, for example, by a typical tension spring varies
linearly with its extension. To offset the linearly increasing
force exerted by the tension spring 310, the counterbalance
mechanism of the present invention employs a snail cam pulley 330,
which operates in conjunction with the tension spring 310 to
provide a relatively constant counter-weighting force.
As best illustrated in FIGS. 8A-B, the snail cam pulley 330
comprises a snail cam wheel 331 secured to a mount 335 by an axle
332, with the axle 332 defining an axis of rotation for the snail
cam wheel 331. The snail cam wheel 331 features a cam track 331a
and a lift track 331b. The cam track 331a has a variable radius
relative to the axis of rotation of the cam wheel 331. A snail
cable 320 (FIGS. 5-7), which is preferably constructed out of nylon
or another synthetic polymer, connects the second end 310b of the
tension spring 310 to the cam track 331a of the snail cam wheel
331, while a lift cable 503 (FIGS. 5-7) connects a synchronized
lift mechanism (discussed below) of the table 1 to the lift track
331b of the snail cam wheel 331. The cam track 331a functions as a
variable lever arm by which the spring force is applied to the
snail cam wheel 331. As the snail cam wheel 331 rotates
counterclockwise (from the top view perspective depicted in FIG.
8B), the effective lever arm decreases. In this arrangement, the
linearly increasing force provided by the tension spring 310 is
converted to a relatively constant force as the snail cam wheel 331
rotates counterclockwise and the snail cable 320 wraps around the
cam track 331a.
The height adjustable table 1 of the present invention, as
indicated above, also features a synchronized lift mechanism that
allows for single-handed, level height adjustment of the work
surface 101 regardless of whether the adjustment force is applied
to the middle, right side, or left side of the top assembly 100. An
embodiment of the synchronized lift mechanism is depicted in FIGS.
9-14. The synchronized lift mechanism comprises first and second
bands 501, 502, which interact with a pulley system positioned
within the base assembly 200 to provide synchronized lifting or
lowering of the top assembly 100.
An exemplary pulley system comprises right and left pulley
assemblies positioned within the right and left telescoping leg
assemblies. The right pulley assembly comprises a first upper
pulley 511, a second upper pulley 512, and an upper lift cable
pulley 513 each mounted to an axle 526 that is secured to the
outside leg 202 of the right telescoping leg assembly. A lower
pulley 514 and a lower lift cable pulley 515 are connected to the
first upper pulley 511 by a right shaft 504 that is suspended
within the internal cavity of the outside, middle, and inside legs
202, 203, 204 of the right telescoping leg assembly. Similarly, the
left pulley assembly comprises a first upper pulley 517 and a
second upper pulley 518 each mounted to an axle 527 that is secured
to the outside leg 202 of the left telescoping leg assembly. A
lower pulley 519 is connected to the second upper pulley 518 by a
left shaft 505, which is suspended within the internal cavity of
the outside, middle, and inside legs 202, 203, 204 of the left
telescoping leg assembly.
The first and second bands 501, 502 are operatively engaged with
the pulley system as described below. As can be seen, for example,
in FIGS. 12-13, the left end 501b of the first band 501 is
connected to the inside leg 204 of the left leg assembly at
attachment point B'. From attachment point B', the first band 501
extends around the first upper pulley 517 of the left pulley
assembly, through a lock assembly 610 as it traverses the housing
102, around the first upper pulley 511 of the right pulley
assembly, down the right shaft 504, around the lower pulley 514 of
the right pulley assembly, and then up the other side of the right
shaft 504, where the first band 501 attaches to the right inside
leg 204 at attachment point A (See FIGS. 11 and 13). Meanwhile, the
right end 502a of the second band 502, as can be seen, for example,
in FIG. 11, is connected to the inside leg 204 of the right leg
assembly at attachment point A'. From attachment point A', the
second band 502 extends around the second upper pulley 512 of the
right pulley assembly, across the housing 102, around the second
upper pulley 518 of the left pulley assembly, down the left shaft
505, around the second lower pulley 519, and up the other side of
the left shaft 505, where the second band 502 attaches to the left
inside leg 204 at attachment point B (See FIG. 12). In this
arrangement, the left and right sides of the lift mechanism are
synchronized, which allows the top assembly 100 to be raised and
lowered evenly regardless of whether the adjustment force is
applied to the middle, right side, or left side of the top assembly
100.
As indicated above, alternative embodiments of the telescoping leg
assemblies may feature the inside legs 204 being attached to the
top assembly 100 and the outside legs 202 being attached to the
foot 210. In such alternative embodiments, one of ordinary skill in
the art will readily appreciate that the upper pulleys 511, 512,
513 of the left and right pulley assemblies will be coupled to the
inside legs 202 of the telescoping leg assemblies, and the first
and second bands 501, 502 of the synchronized lift mechanism will
be connected to the outside legs 202 of the telescoping leg
assemblies.
The height adjustable table's synchronized lift mechanism is
operatively coupled to the counterbalance mechanism by the lift
cable 503, as can be seen, for example, in FIGS. 6 and 11. The
counterbalance force of the extension spring 310 is transmitted to
the synchronized lift mechanism through the lift cable 503. The
lift cable 503 is preferably constructed out of ultra-high
molecular weight polyethylene such as that manufactured by DSM
under the brand Dyneema.RTM.. However, one skilled in the art will
recognize that the lift cable 503, along with the snail cable 320
and the various other cables disclosed herein, can alternatively be
constructed out of a wide variety of materials.
As best illustrated in FIG. 7, a first end of the lift cable 503 is
attached to the lift track 331b of the snail cam wheel 331 (See
FIGS. 8A-8B). The lift cable 503 extends from the snail cam wheel
331, around the upper lift cable pulley 513 of the right pulley
assembly, down the right shaft 504, around the lower cable pulley
515, and then up the other side of the right shaft 504, where the
lift cable 503 attaches to the inside leg 204 of the right leg
assembly (See FIG. 11). The snail cam pulley 330 optionally can
include a bearing 339 attached to the mount 335 to prevent the lift
cable 503 from inadvertently contacting the mount 335 as the top
assembly 100 is raised and lowered.
The degree of height adjustability of the work surface 101 is
correlative to the length of the right and left shafts 504, 505. As
the top assembly 100 is raised, the right and left pulley
assemblies move upwards relative to the inside legs 204. The upward
movement of the right pulley assembly shortens the distance between
the first lower pulley 514 and attachment point A, the point of
attachment for the right end 501a of the first band 501. Similarly,
the upward movement of the left pulley assembly shortens the
distance between the second lower pulley 519 and attachment point
B, the point of attachment for the left end 502b of the second band
502. As a result, a greater portion of the first and second bands
501, 502 is available to transition about the pulley system to
allow for the vertical extension of the top assembly 100.
Additionally, in an exemplary embodiment, each shaft 504, 505
includes a stop member at its lower end (i.e., near the lower
pulleys 515, 519) operable to engage with stop members disposed
within the corresponding inside legs 204, near the top of each
inside leg 204 (i.e., near attachment points A and B). The stop
members on the shafts 504, 505 cooperate with the stop members on
the inside legs 204 to prohibit further movement of the top
assembly 100 relative to the base assembly 200.
In the embodiment depicted in FIGS. 9 and 10, the first and second
bands 501, 502 can each comprise right and left sections joined by
connectors 570, 571, respectively. The connectors 570, 571 allow
for length adjustment of the first and second bands 501, 502 in
order to tune the synchronized lift mechanism over the lifespan of
the table 1. In other embodiments, the first and second bands 501,
502 can be continuous pieces of material. The first and second
bands 501, 502 preferably are constructed out of metallic or
semi-metallic material having a relatively high tensile strength,
such as steel. However, one skilled in the art will recognize that
the bands 501, 502 can alternatively be constructed out of a wide
variety of materials and take on a wide variety of shapes. As used
herein, the terms "band" or "bands" are defined broadly to include
bands, cords, cables, ropes or any other slender length of flexible
material.
Referring now to FIGS. 15-20, the height adjustable table 1 of the
present invention optionally may include a preload mechanism for
balancing the counter-weighting force with the applied load on the
top assembly 100. A disparity between the counter-weighting force
and the load can make counterbalance tables hard to control when
altering the height of the work surface. Such rapid, uncontrolled
movement of the work surface 101 can present a safety risk. This
risk is exacerbated by the fact that tables are often exposed to
varying loads due to the addition and/or removal of objects on the
work surface 101. The preload mechanism of the present invention
allows the counter-weighting force to be easily adjusted by the
user to relatively match the load (i.e., it is load-variable),
thereby eliminating this safety risk while providing a work surface
101 that can be moved up and down with minimal effort.
The preload mechanism embodying the principles of the present
invention can comprise a gearbox 440 connected to the first end
310a of the tension spring 310 by a preload cable 420. The gearbox
440 can include a worm 441 meshed with a worm wheel 442 to form a
worm drive. One end of the preload cable 420 can be attached to the
hub 443 and the hub 443 in turn can be coupled to the worm wheel
442. Moreover, a wormshaft 444 can be attached to, or integrally
formed with, the worm 441, and a handle 410 can be attached to the
wormshaft 444 in order to rotate the wormshaft 444. Optionally, a
thrust bearing 447 can be positioned between the worm 441 and a
housing 445 of the gearbox 440 to reduce friction.
In operation, a user can increase the initial tension or preload of
the tension spring 310 by turning the handle 410 in a first
direction, e.g., clockwise. The rotation of the handle 410 in the
first direction will cause the wormshaft 444 and worm 441 to also
rotate in a first direction. The rotation of the worm 441 will
drive the worm wheel 442 to rotate about its axis, which in turn
will cause the hub 443 to rotate. The rotation of the hub 443 will
cause the preload cable 420 to wind around the hub 443 and
gradually extend the tension spring 310 until the total force
exerted by the tension spring 310 is substantially equal to the
load to be counter-weighted. One skilled in the art will recognize
that the initial tension imparted by the preload mechanism can
subsequently be reduced simply by turning the handle 410 in a
second direction, e.g., counterclockwise.
As shown in FIG. 20, the preload mechanism optionally can include a
load indicator coupled to the first end 310a of the tension spring
310. The load indicator may comprise a load indicator arm 485
attached to the first end 310a of the extension spring 310. As the
user turns the handle 410 to adjust the preload, both the tension
spring 310 and the load indicator arm 485 move laterally. The
positioning of the load indicator arm 485, which is indicative of
the magnitude of the preload, can be viewable from the front of the
table 1 through the load indicator faceplate 480.
In certain embodiments, a torque limiter 430 can be utilized to
protect the gearbox 440 from being damaged due to excessive torque
being applied to the worm 441. A ball detent type torque limiter
430 is depicted in FIGS. 18a-18c. In alternative embodiments, other
types of torque limiters (e.g., shear pin, synchronous magnetic,
pawl and spring, etc.) may be utilized.
Referring to FIGS. 18a-18c, the torque limiter 430 includes a drive
coupling 431, a drive plate 432, a plurality of drive balls 433, a
plurality of springs 434, a driven coupling 435, a set screw 436,
and a plurality of fasteners 437. The drive coupling 431 is
attached to the handle 410 via a driveshaft 412, while the driven
coupling 435 is attached to the wormshaft 444 and secured with the
set screw 436. Torque applied to the drive coupling 431 is
transmitted to the driven coupling 435 through the drive balls 433,
which rest in detents on the drive plate 432 and are held in place
with the springs 434. In an overload condition, when the worm 441
has reached its linear travel limit within the gearbox 440, the
drive balls 433 will separate from the drive plate 432 to disengage
the drive coupling 431 from the driven coupling 435.
Referring now to FIGS. 21-24, the height adjustable table 1 of the
present invention optionally may also include a lock mechanism,
which locks the top assembly 100 at various heights and also
prevents height adjustment of the top assembly 100 if the table 1
is not properly counterbalanced. The lock mechanism may comprise a
release assembly (described below) coupled to a lock assembly 610.
The lock assembly 610 can engage either the first band 501 or the
second band 502 (See FIGS. 7 and 9-12) to prevent movement of the
first band 501 or the second band 502, which in turn prevents
height adjustment of the top assembly 100. The lock assembly 610 is
biased to a locked or engaged position, but can be disengaged to an
unlocked position by actuating the release assembly.
A preferred embodiment of a lock assembly 610 is depicted in FIG.
22. As illustrated, the lock assembly 610 can comprise a lock
housing 611 that contains an upper lock member and a lower lock
member. The upper and lower lock members may include any suitable
locking means known in the art, including but not limited to, a
system of upper rollers and a system of lower rollers or opposing
locking plates. In this embodiment, the first band 501 is routed
through the lock housing 611 such that the upper and lower lock
members are positioned on opposing sides of the first band 501. The
upper and lower lock members are biased towards one another to
engage the first band 501 to prevent its movement, thereby defining
the locked position. Upon actuation of the release assembly, a lock
release member 612 is actuated to cause the upper and lower lock
members to move from the biased, locked position to release the
first band 501. First and second guiding rollers 615, 616 can be
utilized to direct the first band 501 through the lock housing 611.
The lock release member 612 is designed to have a variable pull
weight, which increases as the difference between the load and the
counterbalance force increases. Thus, when the table 1 is not
properly balanced, the pull weight of the lock release member 612
will be increased.
Referring to FIG. 21, the release assembly can comprise an
actuation member 650, a safety spring 630, a first cable 640
connecting the actuation member 650 to the first end of the safety
spring 630, and a second cable 620 connecting the second end of the
safety spring 630 to the lock release member 612. As depicted in
FIG. 24, the actuation member 650 preferably comprises a release
case 651 housing a release paddle 652 coupled to a release cam
653.
In operation, the lock release member 612 can be actuated by
pressing the release paddle 652, thereby causing the release cam
653 to rotate and pull the first cable 640. This movement causes a
tension force that is then transmitted through the safety spring
630 and the second cable 620 before acting on the lock release
member 612. In a preferred embodiment, the safety spring 630 will
deflect and cease to transmit the tension force generated by the
actuation member 650 when placed under a load of 30 lbs. of force
or higher. In this manner, the variable pull weight of the lock
release member 612 functions together with the safety spring 630 to
provide a release override feature, preventing height adjustment of
the top assembly 100 if the disparity between the load and the
counterbalance force reaches a certain level. For instance, if the
disparity between the load and the counterbalance force reaches
approximately 65 lbs., the trigger pull weight will exceed the
capabilities of a tension spring rated at 30 lbs. and the lock
release member 612 will not be actuated.
Referring now to FIG. 23, an alternative embodiment of a lock
assembly 700 is shown. The lock assembly 700 comprises first and
second cam members 703, 705 that are pivotally connected to a base
block 701 with pins 704, 706, respectively. The lock assembly 700
is biased to a locked or engaged position by a spring 707. In
operation, the lock assembly 700 can be actuated, or disengaged
from the locked position, by pressing the release paddle 652,
thereby causing the release cam 653 to rotate and pull the first
cable 640. This tension force is then transmitted through the
safety spring 630 and the second cable 620 before ultimately
causing the cam members 703, 705 to pivot about the pins 704, 706
and release the first band 501.
In a further embodiment, height adjustable table 1 of the present
invention may include an automatically adjustable height adjustment
mechanism that automatically adjusts the height of the top assembly
100 and the attached work surface 101 to a predetermined ergonomic
position associated with an input height. As used in the
specification and claims, "automatically adjustable" is defined as
being moveable by a non-manual force to a predetermined position,
the predetermined position being based on information obtained by
or contained within a device such as a controller, processor,
computer, or database.
In an exemplary embodiment, the automatically adjustable height
adjustment mechanism can electronically adjust the height of the
top assembly 100 to assume an ergonomically proper position for the
user, reducing the need for independent adjustment of the top
assembly 100. The top assembly 100 can include a control panel (not
shown) that is in communication with a processor (not shown) and
the processor in turn is in communication with a database that
contains a list of possible user heights and the predetermined
ergonomic positions associated with each of the possible heights.
The processor and the database can be located within the base
assembly 200 or the top assembly 100 of the table 1. Alternatively,
the processor and/or the database can be located remote from the
table 1, but in wireless communication with each other and/or the
control panel. The processor can be in communication with a
motorized lift mechanism located within either the base assembly
200 or the top assembly 100 of the table 1.
The control panel can include a touch screen with a series of
number scrolls, a slide bar, a number pad, buttons, knobs or other
suitable means accessible to the user for the input of the user's
height. Alternatively, the control panel can include a number of
pre-set height options selectable via a touch screen, buttons, or
knobs. The pre-set height options may include specific heights
(e.g., 5'1'', 5'2'', 5'3'', etc.) or height ranges (e.g., a button
for heights in the range of 4'8'' to 5'0'', a button for heights in
the range of 5'1'' to 5'3'', a button for heights in the range of
5'4'' to 5'6'' and so forth). In another alternative embodiment,
each user has an access ID, with his/her height information
associated therewith, identifiable by the control panel through,
for example, swiping an access ID card or inputting an access ID
code. Near field communication technology, such as embedded within
a user's cellular phone, can also allow the table to recognize the
identity of a user and obtain the height information associated
with that user.
In yet another alternative embodiment, the height of the work
assembly 101 can be communicated to the user as the height of the
top assembly 100 changes, through, for example, a display screen
showing numbers scrolling, an icon indicating height increase, a
slide bar, or a display of changing numbers indicating the height
change. In an even further alternative embodiment, the table 1 can
be equipped with a sensor (e.g., retinal, sonar, laser, IR, motion,
position, and heat detecting sensor, a camera, or other measuring
devices) operable to detect a measurable aspect of a user, such as
the height of a user, and communicate the detected information to
the processor. The sensor(s) can be coupled to the top assembly
100.
As an example, the height adjustable table 1 comprising an
automatically adjustable height adjustment mechanism may be
operated as follows. When a user approaches the height adjustable
table 1, the user may input his/her height at the control panel.
The height information is communicated to and received by the
processor, which communicates with the database to obtain the
predetermined ergonomic position information associated with the
user's input height. Based upon the received predetermined
ergonomic position information, the processor communicates an
instruction to the motorized lift mechanism to adjust the top
assembly 100 to the predetermined ergonomic position. Accordingly,
the work surface 101 automatically adjusts to a height that is
ergonomic for the user, thereby eliminating the need to manually
adjust the height of the work surface.
The foregoing description and accompanying drawings illustrate the
principles, exemplary embodiments, and modes of operation of the
invention. However, the invention should not be construed as being
limited to the particular embodiments discussed above. Many
modifications of the embodiments described herein will come to mind
to one skilled in the art having the benefit of the teaching
presented in the foregoing descriptions and the associated
drawings. Accordingly, it should be appreciated that variations to
those embodiments can be made by those skilled in the art without
departing from the scope of the invention.
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